Chaim Ozer Grodzinski (1863-1940) was born in 1863 in Iuje, Belarus, a small town near Vilna where his father served as Rabbi for forty years, preceded by his grandfather who had also been a Rabbi there for a similar length of time. Rabbi Chaim Ozer was gifted with an infallible memory - never experiencing "forgetting", as he himself remarked, until his old age. At fifteen, he went to the world-renowned Yeshiva of Volozhin. In spite of his tender age, he was immediately accepted into Rabbi Chaim Soloveitchik's select group. By the age of twenty, when he passed through Vilna, his fame preceded him. He followed the suggestion of his father, a pupil of Rabbi Yisrael Salanter, who advised him to marry the daughter of their relative, Rabbi Eliezer Eliyahu Grodzinski, son-in-law of Rabbi Salanter and a the Dayan in Vilna.

Rabbi Chaim Ozer Grodzinski had expected to engage full-time in Torah study in his father-in-law's house, but after two years Rabbi Lazer died, and the community of Vilna requested him to take his father-in-law's place. Since the time of the Vilna Gaon, Vilna never had an official rabbi. Instead, a group of Dayanim formed the rabbinate, all of whom were elderly and great scholars and Poskim. Now the twenty-two year old Rabbi Grodzinski joined their ranks and over the following fifty-five years emerged as the unofficial Rabbi of Vilna, for it was apparent from the start that his vast Torah knowledge was complemented by great wisdom. While Rabbi Chaim Ozer did have a yeshiva, it was not a yeshiva in the usual sense, for he could not give the students much of his time. The group studied independently, and only on Shabbos would the boys gather in his home for discussions. In spite of the limited hours he spent with his pupils, he had vast influence over them and a number of great men emerged from his Kibbutz - among others, Rabbi Moshe Shatzkes, (stepson of Rabbi Yitzchok Blazer), Rabbi Eliezer Silver, Rabbi Avigdor Amiel (later Chief Rabbi of Tel Aviv), Rabbi Yechezkel Abramsky and Dayan Michoel Fisher. Rabbi Grodzinski was also the uncle of Rabbi Eliyahu Eliezer Dessler.

Rabbi Chaim Ozer Grodzinski's brilliance as well as the scope of his leadership are reflected both in the halachic queries that were sent to him from all parts of the world and in the responsa he sent in return. He would write each responsum personally, not entrusting this to a secretary. His mind was so disciplined, that he would simultaneously write a responsum in halachah, give orders to two secretaries, and speak on the telephone. Rabbi Grodzinski authored She'elot uT'shuvot Achiezer, a three-volumed collection of responsa.

As a student of the Yeshiva of Volozhin and as the grandson through marriage of the great Rabbi Yisroel Salanter, Rabbi Chaim Ozer Grodzinski was close to all the great luminaries of the Lithuanian world. He deeply admired and revered the elderly and sagacious Chief Rabbi of Jerusalem Rabbi Shmuel Salant. Rabbi Grodzinski was not yet fifty when Rabbi Shmuel Salant passed away but during the years that they were contemporaries, Rabbi Grodzinski used his vast influence on behalf of the Jerusalem community under Rabbi Salant. He was particularly active in helping ensure that the Rabbi Meir Baal Haneis charity fund was able to meet the financial needs of the Jerusalem community. At the turn of the century Rabbi Shmuel Salant requested that Rabbi Grodzinski help him find an appropriate assistant to help him run the Rabbi Meir Baal Haneis charity and other community matters. Rabbi Grodzinsky strongly urged him to appoint Rabbi Eliyahu Dovid Rabinowitz-Teumim, a great Lithuanian Rabbi who had just arrived in Israel that year. Upon Rabbi Grodzinski's recommendation, Rabbi Eliyahu Dovid Rabinowitz-Teumim joined the Jerusalem Rabbinate as the assistant to Rabbi Salant, and together they worked hand in hand for the benefit of the community until Rabbi Rabinowitz-Teumim's untimely passing in 1905.

Rabbi Chaim Ozer Grodzinski was one of the founders of Agudath Israel and the pillar of the movement throughout his life, personally participating in every Knessia Gedolah as long as his health permitted. He was also honorary president of the movement. When the Moetzes Gedolei HaTorah was established, he was the first chairman and remained so throughout his life. Rabbi Grodzinski was a founding member and administrator of the Vaad HaYeshivos in Lithuania. He also established a network of Jewish schools that provided traditional Jewish education and the Agudas HaRabbanim of Poland. The Chofetz Chaim would not initiate any public action, or sign any public document, until he consulted with Rabbi Grodzinski, considering him to be a living embodiment of Torah.

Rabbi Chaim Ozer Grodzinski passed away in 1940 after a protracted illness. His death prompted massive grief and a huge funeral was held, attended by most of Lithuanian Jewry and many war refugees from Poland, led by the most eminent rabbis of the time. May his memory be a blessing.